In the past, in line connection work such as installation and reconnection of an electronic device or the like, it is not clearly specified on a cable which connector is to be connected to, and thus it is necessary to perform connection after confirming the connector of the device to which the cable is connected at each time. Thus, the line connection work is very cumbersome, and causes improper connection easily, and is inconvenient.
Also, as video becomes super high definition in the recent years, data capacity transmitted between devices dramatically has increased, and it is envisaged that interface between devices changes from electric transmission to optical transmission. In an optical transmission method, a transmittable distance dramatically becomes longer than existing electrical connection even in high speed transmission, and thus it is concerned that connection work between the devices becomes more complex and difficult.
In the optical transmission method, it is proposed to identify whether or not a light signal is transmitted to an optical fiber, by superposing visible light, in a light signal transmission device, as in Patent Literature 1 for example.